Diamagnetism is a property of materials that causes them to be repelled by a magnetic field. This occurs because the electrons in diamagnetic materials create small magnetic fields that oppose an external magnetic field. Common examples of diamagnetic materials include copper, gold, and bismuth. When placed in a magnetic field, diamagnetic materials experience a weak repulsion, which is generally very subtle. Unlike ferromagnetic materials, which can be strongly attracted to magnets, diamagnetic materials do not retain any magnetization once the external field is removed. This unique behavior makes them interesting for various scientific applications.